Summary The entomopathogenic Bacillus thuringiensis serovar israelensis displays peculiar conjugative transfer capabilities, accounted for by the large conjugative plasmid pXO16 (350 kb). The efficient and fast conjugative transfers are accompanied by a macroscopic aggregation of bacterial partners. Moreover, pXO16 has proven capable of effective mobilization and the retro‐transfer of both mobilizable and ‘non‐mobilizable’ pla...

Summary The genetic relationship among 103 natural Bacillus thuringiensis isolates was investigated on the basis of polymerase chain reaction amplification of their specific crystal ( cry ) protein type genes and chromosomal DNA profiling by pulsed‐field gel electrophoresis (PFGE). The strains were recovered from the intestines of small wild rodents and insectivores from the Biebrza National Park and the Łomża Landscape Park o...